Check those outlets!

Nasty fire in this area, last night. Appears one fatality. Woman woke around 2.30 AM to hear 'popping noise, sparks and flames from an outlet. Managed to get herself and 12 year old out, but suffered smoke inhalation. Another young adult is missing; assumed dead. No information yet whether anything was plugged into the outlet etc. Or whether anything was wired non standard etc. Indication so far seems to be that it was the outlet itself that was faulty. House virtually total loss Fire Commisioner's staff on site today to investiagte and probably find remains of the missing person. So recommend; anyone .......... if you suspect an outlet check, immediately switch off that circuit and replace.

Reply to
terry
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Smoke alarms?

Arc fault circuit interrupter? I believe the quality of North American outlets is so poor these are required on bedroom circuits.

Owain

Reply to
Owain

terry wibbled on Thursday 04 February 2010 20:58

Agreed. It's worth giving those sockets a quick feel - even unused sockets. Hopefully you'd feel an over warm socket before it got this bad.

Sockets (more so than lighting[1]) are fairly easy to PIR for the DIYer if you can snaffle a Megger (or equiv)[2]. You have to break into the circuit at the CU, but not at the sockets (for the test, the inspection part would require plates lifting). The test alone can reveal all sorts of problems including miswires, broken rings, bad ring topology, bad connections etc.

[1] In part, because you need to access the CPC everywhere, so easy with a ceiling rose, harder with Class II fittings that may need demounting. And partly because dimmers mess things up, so you need to bridge them. [2] Or low impedance multimeter with good repeatability that can manage 0.1 Ohm or better - this would be a lot better than nothing.
Reply to
Tim Watts

How do those things work, BTW?

Reply to
Andy Dingley

Hmm, I've not heard of that requirement around here, but outlets this side of the Pond are indeed pretty crappy - over time the connections for plug pins go really sloppy.

Matters aren't helped by too many installations where folk have used the "back stab" connections, either (where you just push the bare wire in and in theory it grips) rather than the screw terminals on the sides of the outlet. Heat and vibration and house movement (lots of timber-framed structures here) aren't kind to them.

Reply to
Jules

About the only time I've come across these has been within some fluorescent luminaires. An horrible assembly method obviously devised for cheapness.

Reminds me of the rubber things used to hold tea-towels on the side of a 'kitchen-unit' in the seventies.

TBH, I don't like 'wire-wrap' stuff either, although many swear by it. Give me proper (and properly) soldered joints every time... (And none of this 'lead-free' solder!).

The mantra should be:- 'make a joint that doesn't need soldering, then solder it.'

Reply to
Frank Erskine

I'm not completely convinced that they do, but US and Canadian 'code' incorporates them

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Reply to
ACE

Nothing wrong with them in principle - like any wire termination what's needed is to keep the wire in good contact with the terminal body. A spring is equally as capable of doing this as a screw. After all it's the way a plug and socket works.

Reply to
Dave Plowman (News)

Exactly. It's OK so long as nobody sneezes near it, but prone to failure otherwise. Of course screws can come loose, too, but at least in that situation the stripped end of the wire would have to 'uncoil' around the screw shaft for the joint to fail completely. Shorts seem very unlikely, and the screw terminals on US outlets are designed in such a way that there's not much chance of the wire wobbling and sparking.

I was also amazed the first time I saw a wire nut on house wiring in the US; I thought I was looking at someone's bodge, but no - it's all done like that. Urgh.

cheers

Jules

Reply to
Jules

Thanks for that. I thought it was just me!

Reply to
Clot

UK used ceramic versions thro to 1960 for lighting, they are still being sold. One notable problem can be wire fracture & vibration.

Lookup a modern system like Wago Lever - far superior to even modern push-in systems.

Reply to
js.b1

The message from Jules contains these words:

The typical NEMA 5-15 outlets used in North American installations are horrendous beyond words and in normal use tend to run very hot.

There's also a historic problem in houses wired between the mid 1960s to the mid 1970s with alumin(i)um conductors -- in many designs of receptacle (socket) the clamping arrangements led to creeping of the ductile aluminium and consequet overheating of the reduced contact area and many fires resulted.

Plugs area also often very poor quality -- just bent brass strips for "pins."

Better-quality plugs and sockets are made, but are not generally available retail.

The use of "wire nuts" should be familiar to anyone working with 1950s UK wiring -- really just a plastic version of the "Scruit."

Reply to
Appin

Wirenuts are still being used in new lighting fittings. Not sure whether this is compliant or not.

NT

Reply to
NT

the rest of the world used to use 60 years ago, and then mandates the use of devices to detect the connections starting to burst into flames to solve that problem of crappy wiring practice. Mandating modern wiring would seem to me to be much more sensible. That's how the rest of the world solved the problem of electrical installations bursting into flames 50+ years ago.

Reply to
Andrew Gabriel

Andrew Gabriel wibbled on Friday 05 February 2010 20:29

Just out of interest, what's the deal with US socket outlets?

120VAC I know about - but how many amps max per socket and per circuit? Any plugtop fusing?

They also have some 240VAC outlets for big loads don't they Is this based on a 120-0-120 supply?

Are RCDs (GFCIs) mandatory? Is everything 3 phase distribution (or is that 6 phase)?

Reply to
Tim Watts

I don't recall ever seeing a fused plug over here, and they're not that common in devices, either; most equipment seems to rely on something going bang back at the service panel (i.e. consumer unit / fusebox) before things catch fire.

Generally you get three types of 120V outlets:

15A neutral and 'hot' but no ground, 15A neutral, hot and (round) ground pin socket, 20A neutral, hot and ground; the neutral is a '-|' shape

then wiring: #14 wire rated for 15A, #12 for 20A #10 for 30A

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240V sockets and wiring are both incredibly chunky - looks like it was all designed in the 1940s :)

Not sure exactly what current rules are - but GFCIs are mandatory for kitchens (at least near sinks), bathrooms, and outbuildings. I've seen lots of complaints about the latter because of the issues they have with chest freezers, as commonly found in garages. Lots of folk seem to initially fit a GFCI socket there and then replace it with a normal socket for everyday use, then swap the GFCI back if they move in order to sell the house.

I still see a lot of good ol' fuseboxes around; we've got five on our property, along with a couple of service panels full of more modern breakers.

cheers

Jules

Reply to
Jules

Mostly 15A sockets IME on 20A circuits. Would be lucky to get a rating of 2.5A @ 50V in any other country.

Yes. The outlets used for this vary.

I don't know exact regs. I believe they are mandatory in bathrooms. It also seems to be mandatory to supply hairdriers with RCD plugs molded on, so you often end up with both.

I found one that didn't trip in a hotel and commented on that. Got a lot of comments back that it is very common for them not to work and no one has noticed. They are usually 5mA trip.

You can do things such as put an earthed socket on a circuit with no earth, if it's an RCD socket (or there's one upstream, since you can diasy-chain from the RCD protected side).

Single phase up each street, can't recall exactly the voltages, but values roughly between 4kV and 12kV IIRC. The single phase is typically taken from one of 3-phases running past the ends of the streets.

These are transformed down to 120-0-120V in dustbin style transformers up the poles, each feeding 2-4 homes (the drop wires can't go very far because the regulation of 120V goes to pot at high currents).

The "dustbins" are famous for overheating and catching the oil alight, raining it down on the pavement^H^H^H^H^H^H^Hsidewalk. I watched one burning out once (1995, IIRC). They also look a bit like a beer can on a pole to those who walk around with guns, and do get shot at. I was involved in some telecoms kit which was being made for the US, and the spec includes being bullet proof for exactly this reason.

Reply to
Andrew Gabriel

They were never common in UK mains wiring, but ceased well before WWII. There was however something which looked very similar and is probably the predecessor of the chocolate block - it was a ceramic case like the wirenut outer, with a brass terminal inside and a grub screw through the side to clamp the conductors in the brass insert. Very common in conduit wiring systems between the wars.

Wirenuts were available and used for things like wireless aerials and battery circuits. You will surely find them occasionally misused on mains, just as you will every other type of inappropriate connector.

I don't believe it conforms to the regs for what it's being advertised for, but I haven't looked at one closely.

No, they're insulated crimps. With some, the plastic springs back to the original shape after crimping so they don't look like crimps, but you won't get the wires out. I did a double-take when I first saw one, until I realised what it is.

Reply to
Andrew Gabriel

The message from Jules contains these words:

Things like electric stoves usually have a plug and socket connection. Older-style stoves (maybe some still do) adjusted temperature on the rings by switching two elements so that they operated either singly, together, in series or parallel on 120 or 240 volts.

Not a total truth. Some, like those intended for stoves (cookers) are indeed extremely chunky. Others, like the NEMA 6-15 and 6-20 are very neat. Often used for room-size air conditioners.

Reply to
Appin

The message from snipped-for-privacy@cucumber.demon.co.uk (Andrew Gabriel) contains these words:

The trouble is that the US accessories are based on a design dating back to 1904 and in general use by 1915 and there's never been a basic change in that design so there's been no general forced upgrading of installations such as has taken place in many or most other countries. It's not at all uncommon to find post and wire installations still functioning (individual insulated conductors on porcelain insulators).

Reply to
Appin

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